The present invention relates to a tonneau cover for a pick-up truck cargo a box and in particular to a ball and socket latch for attaching the rear or tailgate rail of the tonneau cover frame to the frame side rails.
Several different types of tonneau covers have been developed for covering the cargo box of a pick-up truck. One popular type of tonneau cover is a soft cover employing a flexible sheet, such as an automotive type of vinyl sheet, to cover the cargo box. The flexible sheet has fasteners about its periphery which are used to attach the sheet to a rectangular frame. The rectangular frame is attached to the sidewalls of the cargo box. A typical frame includes side rails which are positioned on the cargo box sidewalls and clamped, coupled or otherwise secured thereto. Front and rear frame rails are attached to the two frame side rails to complete the rectangular frame. The front rail rests upon the front wall of the cargo box while the rear rail rests upon the tailgate. The front and rear rails are typically not themselves attached to the cargo box. The frame is held in place solely by attaching the side rails to the cargo box.
Since the rear frame rail is not fastened to the tailgate, it is possible to leave the tonneau cover in place and lower the tailgate to access the cargo box to load objects which fit under the tonneau cover. To load larger objects, it is necessary to remove the flexible sheet. This is done by releasing the flexible sheet from the side rails and the rear frame rail. The cover is rolled forward and is tied to the front rail of the frame at the front of the cargo box. When the tailgate is opened, it is necessary to remove the rear frame rail which spans across the now open rear of the cargo box in order to load large objects. Thumb screws are typically used to attach the rear frame rail to the frame side rails so that the rear rail can be easily removed without the use of tools when necessary. However, when the rear frame rail is not in use and is lying in the cargo box, it is possible for the thumb screws to vibrate loose from the rear rail and become lost. In addition, thumb screws are expensive compared to regular screws and other fasteners.
Accordingly, it is an object of the present invention to provide a fastening means for attaching the rear rail of the tonneau cover frame to the side rails which cannot become separated and lost.
It is a further object to provide a fastening means which does not require tools to remove and re-install the rear rail.
The tonneau cover of the present invention attaches a rear frame rail to the two side rails with the use of a ball and socket latch at each end of the rear rail. The latch end includes a ball which is spring biased into an aperture in the side rails to latch the rear frame rail in place. The ball is carried in a housing which is fixed to one of the die cast corner blocks of the tonneau cover frame. The corner blocks each have a forward extending leg which is inserted into the rear end of one of the side rails. A spring pushes the ball so that it projects through an opening at the end of the cylinder. The ball extends sufficiently to project into an aperture in the side rail. This latches the rear frame rail to the two side rails. The biasing spring provides sufficient force to hold the rear frame rail in place so that during vehicle operation, without the tonneau cover attached, the rear rail is retained on the two side rails.